Alert archive / Louisiana / Tornado Warnings in 2021

Tornado Warning 7, NWS Shreveport, LA

March 17, 2021Union Parish, Louisiana

NWS Shreveport, LA issued this tornado warning at Mar 17, 2021, 3:34 PM CDT for Union Parish, Louisiana. It was in force for 10 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Mar 17, 2021, 3:34 PM CDT (20:34 UTC)
Expired: Mar 17, 2021, 3:44 PM CDT
In force: 10 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Union Parish, LA

The radar

The Shreveport radar (KSHV), 170 km from the middle of the area, began a volume at 20:33 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Mar 17, 12:57 PM CDT	Tornado Watch PDS	SPC	6 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 8.6 hours before the alert went out and 161 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1417 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 682 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 328 m²/s²
0-3 km storm-relative helicity: 340 m²/s²
Significant tornado parameter: 2.7
Supercell composite: 14.5

Open this sounding in Storm Lab

The text

As transmitted.

792 
WFUS54 KSHV 172034
TORSHV
LAC111-172100-
/O.NEW.KSHV.TO.W.0007.210317T2034Z-210317T2100Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Shreveport LA
334 PM CDT Wed Mar 17 2021

The National Weather Service in Shreveport has issued a

* Tornado Warning for...
  Northeastern Union Parish in north central Louisiana...

* Until 400 PM CDT.
    
* At 333 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 11 miles north of Sterlington, or 13 miles west of
  Bastrop, moving northeast at 40 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This tornadic thunderstorm will remain over mainly rural areas of
  northeastern Union Parish, including the following locations...
  Spencer, Linville, Haile and Marion.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3272 9214 3285 9226 3301 9209 3301 9207
      3298 9208 3297 9207 3297 9208 3292 9207
      3292 9208 3287 9208 3284 9206 3282 9207
      3280 9205 3278 9205
TIME...MOT...LOC 2033Z 225DEG 33KT 3285 9212 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

44

1 follow-up statement

670 
WWUS54 KSHV 172044
SVSSHV

Severe Weather Statement
National Weather Service Shreveport LA
344 PM CDT Wed Mar 17 2021

LAC111-172054-
/O.CAN.KSHV.TO.W.0007.000000T0000Z-210317T2100Z/
Union LA-
344 PM CDT Wed Mar 17 2021

...THE TORNADO WARNING FOR NORTHEASTERN UNION PARISH IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 700 PM CDT for north central
Louisiana.

LAT...LON 3272 9214 3285 9226 3301 9209 3301 9207
      3298 9208 3297 9207 3297 9208 3292 9207
      3292 9208 3287 9208 3284 9206 3282 9207
      3280 9205 3278 9205
TIME...MOT...LOC 2039Z 225DEG 33KT 3292 9203 

$$

44

The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 17, 2:45 AM CDT	Lake Wind Advisory	SHV	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more	40 hr
Mar 17, 8:34 AM CDT	Severe Thunderstorm Warning	SHV	Bossier, Caddo	56 min
Mar 17, 8:40 AM CDT	Severe Thunderstorm Warning	SHV	Caddo	44 min
Mar 17, 9:29 AM CDT	Severe Thunderstorm Warning	SHV	De Soto, Sabine	61 min
Mar 17, 9:31 AM CDT	Special Weather Statement	SHV	Bossier, Caddo, Webster	59 min
Mar 17, 10:29 AM CDT	Special Weather Statement	SHV	De Soto	61 min
Mar 17, 10:36 AM CDT	Special Weather Statement	SHV	Claiborne, Webster	39 min
Mar 17, 11:02 AM CDT	Special Weather Statement	SHV	Bienville, Red River, Webster	43 min
Mar 17, 11:46 AM CDT	Special Weather Statement	SHV	Bienville, Jackson, Red River	59 min
Mar 17, 12:36 PM CDT	Special Weather Statement	SHV	Natchitoches, Red River, Sabine	39 min
Mar 17, 2:08 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, Jackson, Lincoln, Ouachita, Union	52 min
Mar 17, 2:16 PM CDT	Severe Thunderstorm Warning	SHV	Claiborne, Lincoln, Union	44 min
Mar 17, 2:32 PM CDT	Tornado Warning	SHV	Union	43 min
Mar 17, 2:58 PM CDT	Tornado Warning	SHV	Lincoln, Ouachita, Union	47 min
Mar 17, 3:12 PM CDT	Tornado Warning	SHV	Jackson, Lincoln, Ouachita, Union	48 min

Nearby

Tornado Warnings in Louisiana, 2021 Every tornado warning in 2021 Tornadoes in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.